<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		div {
			/*我们用css 边框可以模拟三角效果*/
			width: 0;
			height: 0;
			border-top: 10px solid red;
			border-right: 10px solid green;
			border-bottom: 10px solid blue;
			border-left: 10px solid pink;
		}
		p {
			width: 0;
			height: 0;
			border-style: solid;
			border-width: 10px;
			border-color:  transparent transparent transparent red;
			font-size: 0;
			line-height: 0;
		}
	</style>
</head>
<body>
	<div></div>
	<p></p>
</body>
</html>